Sealing system having interlocking inner diameter seal element to resist pressure changes

ABSTRACT

Gasket seals for high pressure applications include retaining elements with inner diameter seal elements that interlock with the retaining element to provide resistance to movement in both axial and radial directions between the retaining element and seal element. High pressure sealing may be accomplished using a metallic core retaining element to which an electrically isolating material is bonded on either or both sides. Sealing is achieved through an inner diameter dielectric sealing element, such as a polytetrafluoroethylene (PTFE) inner diameter sealing ring. Flanges of a joint in a fluid flow ling may be bolted together with the gasket seal interposed therebetween. In the event of pressure changes, the inner diameter seal resists being drawn into the flow line, and resists axial movement relative to the retaining element, through dual locking members that secure the seal to the retaining element.

The present application is a continuation in part of U.S. Design patentapplication Ser. No. 29/640,610, filed Mar. 15, 2018, and the presentApplication is a continuation in part of U.S. patent application Ser.No. 14/606,306, filed Jan. 27, 2015, and claims priority to U.S.Provisional Patent Application Ser. No. 61/932,880, filed Jan. 29, 2014,the disclosures of which is incorporated herein by reference as if setout in full.

FIELD

The present disclosure relates generally to an isolation gasket which isadapted to be interposed and compressed between joined pieces of pipe ina flow line that is operative for fluid flow therethrough withoutleakage. The seal device of the present disclosure is specificallyadapted to resist pressure changes in a flow line through an innerdiameter seal element that is interlocked to a retaining element.

BACKGROUND

Seal systems using gasket devices are well known and have been used in avariety of applications to prevent fluid from leaking between joinedpieces. For example, a seal device is interposed and compressed betweenflanged end connections of a flow line. In some cases, in-line processcontrol equipment is to be installed at various points in a flow lineand may be associated with flanged end connections of a flow line.In-line process control equipment may include such things as valves,pumps, flow meters, temperature controllers, pressure controllers andthe like. In addition, ends of pipe sections are provided with flangesso that the sections may be connected, end-to-end, to form the flowline. It is known to provide gasket devices at the interfaces of thejoined sections to prevent leakage of the fluid at the joint.

Regardless of the nature of the joint, that is, whether it is betweenthe joined sections of pipe or whether for some other purpose, such as,for example, joints used to connect in-line process control equipment,it is desirable for a gasket device and seal system to be selected basedon various factors that are associated with a particular joint and theparticular media that is conveyed through the joint. These factorsinclude the corrosive nature of the media flowing through the pipe lineas well as the physical characteristics of that flowing media. Suchphysical characteristics include the pressure, temperature and velocityof the media, as well as anticipated changes in the pressure (includinga dramatic change in pressure due to rupture), temperature and velocityof the media. Additionally, in many cases it is also necessary to notonly provide a reliable seal for the joint but to also electricallyisolate one side of the joint from the other.

SUMMARY

The technology of the present application recognizes that a sealingsystem that can contain high pressures and provide an inner diameterseal element that can withstand significant changes in pressure would bea significant improvement in the field of effective flow line sealing.Embodiments disclosed herein provide sealing systems for high pressureapplications. The sealing systems comprise one or more retainingelements having an inner diameter with one or more inner diameter sealelements. The inner diameter seal element(s) interlocks with an innerdiameter portion of the retaining element(s) to provide resistance tomovement in at least a radial direction between the retaining element(s)and seal element(s). The retaining element(s) provide resistance tomovement in both the outer and inner radial direction. In one aspect ofthe technology, high pressure sealing is accomplished using a metalliccore retaining element to which an electrically isolating material maybe bonded on either or both sides. Sealing is achieved through an innerdiameter dielectric sealing element, such as a polytetrafluoroethylene(PTFE) inner diameter sealing ring. The inner diameter sealing ring maybe a flat or profiled surface, such as, for example, a kammprofile.Flanges of the joint may be bolted together with the seal interposedtherebetween. In the event of pressure changes, the inner diameter sealresists being drawn into the flow line and resists axial movementrelative to the retaining element through the locking member(s) thatsecure the inner diameter seal element to the retaining element. Inadditional aspects, the technology may be provided with otherconfigurations including, one or more backup seals in the retainingelement, one or more backup seals in the inner diameter seal, and one ormore compression limiters within either the inner diameter seal or theretaining element.

In one aspect, the technology of the present application provides agasket seal apparatus for use between joined pieces in a flow line thatis operative for fluid passage therethrough. The gasket seal comprises(A) a retaining ring having opposing side surfaces and an inner diameteropening formed therein, the retaining ring comprising: a radial lockfeature forming a circumferential rim about the inner diameter opening;and (B) an inner diameter seal element having an inner seal surface, anouter seal surface, and a locking portion, the locking portioncomprising: a leg and a lip that cooperatively engage with said radiallocking feature, wherein the cooperative engagement substantiallyprevents relative radial movement between the retaining ring and theinner diameter seal element. The radial locking features and members areinterlocked so as to substantially prevent radial movement between theretaining ring and the inner diameter seal element. The retaining ring,in one aspect, may have a metal core and a layer of dielectric materialdisposed on at least one of said opposing side surfaces. The retainingring may further include a groove formed on each of the opposing sidesurfaces and a secondary seal element disposed in each of the grooves.

In one embodiment, the radial locking feature comprises a radiallyextended flanged surface and projection forming a recess in theretaining ring and the radial locking member on the inner diametersealing element comprises a complimentary flanged surface and projectionforming a recess to allow interlocking of the retaining ring and lockingmember. The inner seal surface may have a chevron-shaped pressureactivated surface, for example.

In another aspect, the present disclosure provides a gasket sealapparatus for use between joined pieces in a flow line that is operativefor fluid passage therethrough. The gasket seal comprises (A) aretaining ring comprising a core material having a core inner surface, afirst side surface, and a second side surface opposing the first sidesurface, a first layer of surface material coating the first sidesurface and a second layer of surface material coating the second sidesurface, wherein: (i) the core material comprising a recess in the firstside surface wherein said recess forms an inner diameter circumferentialring, (ii) the first layer of surface material comprising acircumferential groove in a first material inner surface, wherein thefirst material inner surface is placed radially outward of the coreinner surface, and (iii) the second layer of surface material comprisinga second material inner surface substantially aligned with the coreinner surface; and (B) a seal element having an inner seal surface, anouter seal surface, a hook, and an axial lock protrusion, wherein: (i)the hook comprises a leg and a lip that form a recess with the outerseal surface such that the recess cooperatively engages the rim toprevent relative radial movement between the retaining ring and the sealelement; and (ii) the axial lock protrusion extends from the leg of thehook and cooperatively engages the circumferential groove to preventrelative axial movement between the retaining ring and the seal element.

In still a further aspect, the present disclosure provides an isolationsystem that provides an interface between joined flange pieces, eachhaving an inner and an outer face, in a flow line that is operative forfluid passage therethrough, comprising: a gasket seal comprising (A) aretaining ring having opposing side surfaces and an inner diameteropening formed therein, the retaining ring having (i) an axial lockfeature comprising a rectangular groove formed on said inner diameteropening, and (ii) a radial lock feature comprising a rectangular recessand rim formed on said inner diameter opening, and (B) a seal elementhaving an inner seal surface and an outer seal surface, the outer sealsurface comprising (i) an axial lock protrusion engaged with therectangular groove, and (ii) a radial lock member engaged with therectangular recess and the rim, wherein said axial and radial lockfeatures and members are cooperatively engaged so as to substantiallyprevent relative axial and radial movement between said retaining ringand the seal element; at least one insulating sleeve receivable in analigned bore formed in each joined flange piece, the sleeve having alength that is substantially equal to a distance between outer faces ofthe joined flange pieces with the gasket seal interposed therebetween;at least one elongate metal fastener having opposing ends, the fastenerbeing receivable in the insulating sleeve for connecting joined flangepieces to one another with the gasket seal interposed therebetween; andat least one insulating washer receivable on the at least one elongatemetal fastener abutting at least one of the flange piece outer faces.The metal fastener may further comprise a metal shaft threaded toreceive a nut on at least one of the opposing ends. The retaining ringmay further comprise a groove formed on each of the opposing sidesurfaces and a secondary seal element disposed in each of the grooves.The radial locking feature, in an embodiment, comprises a wedge-shapedrecess formed in the retaining ring, and the radial locking membercomprises a complimentary wedge-shaped projection that extends into thewedge-shaped recess. The axial locking feature, in an embodiment,comprises a semi-circular shaped recess formed in the retaining ring,and the axial locking member comprises a complimentary semi-circularshaped projection that extends into the semi-circular shaped recess.

These and other advantages and novel features of the disclosure will beset forth in part in the description which follows, which disclosesvarious embodiments, including the currently preferred embodiment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view, partially in cross-section, showing an isolationgasket and sealing system according to a first exemplary embodiment ofthe present disclosure;

FIG. 2 is an enlarged side view in partial cross-section showing arepresentative nut and bolt set used with various insulating componentsfor electrically isolating a flange joint for various exemplaryembodiments;

FIG. 3 side cross-section view of one-half of a flange joint showing agasket according to an exemplary embodiment;

FIG. 4 is a cross-sectional view of the inner-diameter sealing member ofa gasket for an exemplary embodiment;

FIG. 5 is a cross-sectional view of a retaining member of an exemplaryembodiment;

FIG. 6 is a cross-sectional view of a retaining member of anotherexemplary embodiment;

FIGS. 7A-7C are cross-sectional views of pressure activated seal membersaccording to several exemplary embodiments;

FIGS. 8A-8D are cross-sectional views of seal members with differentvertical locking elements according to several exemplary embodiments;

FIGS. 9A-9C are cross-sectional views of seal members with differentradial locking elements according to several exemplary embodiments;

FIG. 10 is a cross-sectional view of a retaining member of an exemplaryembodiment; and

FIG. 11 is a cross-sectional view of the sealing member of a gasket foran exemplary embodiment.

FIG. 12A is an elevation view of another annular sealing member of anexemplary embodiment.

FIG. 12B is a cross-sectional view of the annular sealing member of FIG.12A

FIG. 12C is a detail of the cross-section of FIG. 12B.

DETAILED DESCRIPTION

For a more complete understanding of the technology of the presentapplication, reference is now made to the following detailed descriptionof several exemplary embodiments as illustrated in the drawing figures,in which like numbers represent the same or similar elements. Variousembodiments are described herein, with specific examples provided inmany instances to serve to illustrate and discuss various conceptsincluded in the present disclosure. The specific embodiments andexamples provided are not necessarily to be construed as preferred oradvantageous over other embodiments and/or examples. Furthermore,concepts described herein may be used with numerous different variationsof sealing gaskets and sealing systems. For example, an inner diameterseal may be used with a retaining member and secondary sealing elementsand/or compression limiter such as described in U.S. Pat. No. 7,976,074,issued Jul. 12, 2011, entitled “ISOLATION GASKET, SYSTEM, AND METHOD OFMANUFACTURE,” the entire disclosure of which is incorporated herein byreference as if set out in full.

As mentioned above, the technology of the present application provides,among other things, a solution to problems that may occur with currentlyknown inner-diameter seals in that the seal can collapse into the boreof the piping system during variations in piping pressure, includingrapid decompression of the piping pressure, when a vacuum is pulled intothe piping systems, and/or when suction is caused by the flow of themedia past the seal. Having the seal collapse into the bore can causesignificant problems as, in certain situations, when the system isrepressurized the media will escape past the collapsed seal, come intocontact with the retainer, and possibly escape to the environment oroutside of the piping system. Further, the collapsed seal may betransported down the piping system where it may cause other problemssuch as obstructions with other piping components, damage or the like tomoving components such as pumps or the like, contamination of processingsystems, and/or jamming of pigging operations, to name a few.

The technology of the present application is generally directed to anisolation gasket adapted to be used in a joint that inhibits, prevents,or substantially reduces the likelihood of a seal collapse into the boreof the joint, which generically is in a piping system. Such joints maybe a flange connection between two sections of pipeline, which areconnected in end-to-end relation. In other aspects, the joint may be aconnection used to connect monitoring equipment to the flow line, whichmay be flanged or other types of connections. Other joints may notinclude flanged surfaces as the above referenced conventional joints.Accordingly, the technology disclosed in the present application isdescribed in reference to a conventional flanged connection such as, forexample, the flanged connection used with end-to-end connection of apair of pipeline sections, but it should be clearly understood that thepresent invention is not limited to such flanged connections.

With reference now to FIG. 1, a sealing gasket 10 is located in a flangeconnection 12 between two pipe sections 14 in a flow line application.Each of pipe sections 14 includes flanges 16 which may be placed inconfronting relationship with gasket 10 therebetween. Flanges 16 areprovided with bores 20 which align with one another so that flanges 16may be connected by nut 32 and bolt 18 sets, as is known in the art.

With continued reference to FIG. 1, and with reference to FIG. 2, someembodiments provide for electrical isolation between flanges 16, whichmay be accomplished by a plurality of different components associatedwith each aligned pair of bores 20. In this embodiment, a pair ofaligned bores 20 is provided with a non-conductive sleeve 22constructed, for example, of a glass reinforced polymer although othermaterials, such as epoxy, phenolic and nomex materials may be suitablyemployed. Sleeve 22 is dimensioned to have a length that is about thesame as the distance between outer surfaces 24 of flanges 16 and thethickness of gasket 10 interposed therebetween. Once sleeve 22 has beeninserted into a pair of aligned bores 20, insulating washers 26 areplaced on either side of bores 20 on outer surfaces 24 of flanges 16. Inthis embodiment, optional metal washers 28 are then positioned againstwasher 26 and bolt 30 is passed through the washers and sleeve 22 afterwhich it is secured by nuts 32. In some cases, the insulating washers 26may have metallic cores for strength and the like such that the optionalmetal washers 28 are not necessary. This assembly is undertaken for eachof the aligned bores 20 after which nuts 32 may be tightened to compressgasket 10 at a desired pressure. Rather than nuts 32 on opposing sidesof the nut 32 and bolt 18 set, the bolt 18 may be provided with a headin place of one of the nuts 32.

To facilitate electrical isolation between the pipe sections 14, thegasket 10 may include an outer layer of a dielectric material. Thus,various embodiments described herein contemplate a gasket 10 having adielectric coating on one or both sides, insulating washers 26, andnon-conductive sleeves 22, to provide electrical isolation of separatepipe sections 14. The dielectric coating is only required to be onconductive portions of the gasket 10. Insulating washers 26, asillustrated in FIGS. 1-2, are positioned against outer surfaces 24 offlanges 16 and, in combination with sleeve 22, provide electricalisolation between the nut 32 and bolt 18 sets and the flanges 16. Theinsulating washers 26 may be metal core washers that are coated with adielectric material. Similarly, the dielectric outer layer on the gasket10 provides electrical isolation between the confronting flangessurfaces of flanges 16.

FIG. 3 illustrates a cross-section of a portion of a flange connectionhaving a gasket 50 consistent with the technology of the presentapplication. The gasket 50 in this example includes a retaining ring 54and an inner diameter seal element 58. The inner diameter seal element58 is sized to fit within the inner diameter of the retaining ring 54.The retaining ring 54, in this embodiment, has a metal core 62 and acoating of material 66 on each side of the metal core 62. In otherembodiments, the gasket 50 may have a non-metallic core for strength.When the gasket 50 has a non-metallic core, the coating of material 66may not be necessary for electrical isolation. In one exemplaryembodiment, the coating of material 66 is a dielectric material. Thecoating of material 66 may comprise a sealing material, such aspolytrafluoroethylene (PTFE) or other fluorinated polymer to allow thecoating material to act as a secondary seal should the seal element 58fail. In another aspect, the coating material 66 may be a copolymerPTFE, such as, a composite of PTFE and polyfluoroethylene (PFE). Whenthe coating of material 66 is a dielectric material, the retaining ring54 provides electrical isolation between flanges 70. The flanges 70connect pipe sections 74, and include axial bores 78 that may receivebolts and nuts assemblies, such as the aforementioned bolts 18 and nuts32, or other means to couple the joint components together under acompressive loading. To facilitate electrical isolation, isolationsleeves 22 may be provided along with isolation washers 26 to secure theflanges 70 together in a manner similar as described above with respectto FIGS. 1 and 2. Alternatively, the bolts 18 and nuts 32 may be madefrom an electrically inert material. As can be appreciated now, onreading the disclosure and reviewing the figures, the seal element 58comprises a dielectric or non-conducting material, such as, for example,the aforementioned PTFE or other fluorinated polymer to name but twopotential compositions for the seal element 58.

In the embodiment of FIG. 3 the inner diameter seal element 58 and theretaining ring 54 include one or more locking mechanisms 55 that helpsecure the inner diameter seal element 58 to the retaining ring 54.Generally, the locking mechanism 55 includes a first portion on theretaining ring 54 and a second portion on the seal element 58 thatcouple to provide a lock between portions. The locking mechanisms 55described in the present application may be interchangeable between theseal element 58 and the retaining ring 54 although the features may onlybe described on one or the other. FIG. 4 illustrates a cross section ofthe inner diameter seal element 58 of this embodiment, and FIG. 5illustrates a cross section of the retaining ring 54 of this embodiment.In the exemplary embodiment shown in FIGS. 4 and 5, the retaining ring54 includes a radial locking element 82 and an axial locking element 86.As used herein, the radial direction is along the radius of a crosssection of the joint and the axial direction is along the media flowdirection associated with the joint. The inner diameter seal element 58includes a complimentary radial locking feature 90, and axial lockingfeature 94. In this manner, the radial locking element 82, andcomplimentary radial locking feature 90 interlock to help retain theinner diameter seal element 58 to the retaining ring 54 and preventrelative radial movement between the two. In prior designs withoutradial locking feature, pressure changes within the flow line couldpotentially result in an inner diameter seal delaminating from theassociated retaining member and being drawn into the flow line,resulting in loss of seal at the flange joint, and possibly otherundesirable consequences. The axial locking element 86, andcomplimentary axial locking feature 94 also interlock to help retain theinner diameter seal element 58 to the retaining ring 54 and preventaxial movement between the two. In this embodiment the radial lockingelement 82 and complimentary radial locking feature 90 are interlockedthrough an inclined, or wedge-shaped, surface, such that in order todisengage the radial locking element 82 and radial locking feature 90the seal element 58 would need to be moved in an axial directionrelative to the retaining ring 54. The axial locking element 86 and theaxial locking feature 94 work to prevent such movement, thereby helpingto keep the inner diameter seal element 58 engaged to the retaining ring54, which also reduces the tendency of delamination between the innerdiameter seal element 58 and the retaining ring 54. In such a manner,the complimentary radial and axial locking mechanisms between the innerdiameter seal element 58 and the retaining ring 54 help to prevent theintrusion of the seal into the bore during pressure changes, such asnegative pressure, rapid decompression or suction from the media that isflowing through the pipe sections 74.

The inner diameter seal element 58 may be formed from any of a number ofsealing materials. In an exemplary embodiment, the seal element 58 isconstructed of a chemically inert material, such as, PTFE that is heldin place by the retaining ring 54. The inner diameter seal element 58,in an embodiment, is machined from a billet of PTFE material, althoughother types of material may be used, such as rubber or other types ofelastomeric material. Also, instead of machining, the PTFE may bemolded, extruded, or formed using other methods of formation. In theembodiment of FIGS. 3 and 4, the inner face of inner diameter sealelement 58 seal is made in a chevron style configuration that ispressure activated and effects sealing of the piping media between theflanges 70. In other words, the inner diameter seal element has an innerradial surface that forms a V or concave shape such that the pressure ofthe media being sealed provides a sealing force tending to straightenthe inner radial surface and causing a sealing force to be applied. Ofcourse, the inner diameter seal element 58 may have one of any number ofdifferent configurations that provide sealing of the piping media otherthan the V or concave shape, and a few examples of such V or concaveconfigurations are illustrated in FIGS. 7A through 7C. It will bereadily recognized by one of skill in the art that the inner diametersealing element 58 may have various other configurations that may beselected based on a particular application in which the seal is to beused.

The retaining ring 54 may be constructed of many various materials suchas polyimide, glass reinforced epoxy, carbon steel, stainless steel, ora “sandwich” of steel with laminate material bonded on either side suchas illustrated in FIGS. 3 and 5. As can be appreciated, the retainingring 54 is shown having flat opposed surfaces. In some aspects, theretaining ring 54 may be used as a secondary seal in which case theprofile may be a kammprofile comprising a series of ridges and groovesor a convex surface opposed to the relatively flat flanged surface shownin FIG. 3.

The retaining ring 54 may be machined, molded, or otherwise shaped witha corresponding shape as the outer surface of the inner diameter sealelement 58 to accept the interlocking features of the inner diameterseal element 58. The retaining ring 54 may have a sufficient outerdiameter to sit on the bolts of the flanges 70. Thus, to align theretaining ring 54, and hence the inner diameter sealing element, theretaining ring 54 is received on a bolt 18 (with or without an isolationsleeve 22). The retaining ring 54 acts, in this case, as a gasketcentralizer to ensure the gasket 50 is properly aligned to the flangebore. In one exemplary embodiment, the retaining ring 54 is aligned toone of the flange 70 faces and the inner diameter seal element 58 isthen assembled onto the retaining ring 54 to create the gasket 50 priorto securing the flanges 70 together with bolts through the axial bores78 to create a seating stress acting on the lateral faces of the innerdiameter seal element 58, thereby preventing media from escaping theassembly. If electrical isolation is required, then isolation sleevesand washers will be included in the package, similarly as describedabove with respect to FIGS. 1 and 2.

In certain aspects of the technology disclosed herein, the retainingring 54 may include one or more grooves that contain secondary sealelements and/or compression limiters. A retaining ring 100 of anexemplary embodiment is illustrated in FIG. 6. In this embodiment, theretaining ring 100, similarly as retaining ring 54, has a metal core 62and a coating of material 66 on each side of the metal core 62 toprovide electrical isolation between flanges in a flow line. Theretaining ring 100 includes a groove 104 located on at least one side,and in some aspects on both sides as shown in FIG. 6, of the retainingring 100. Notice the grooves 104 in the exemplary embodiment are shownas vertically aligned in the radial direction. In certain aspects, thegrooves 104 may be offset in the radial direction. A secondary sealingelement, such as an o-ring, an E-seal, a spring-energized PTFE lip seal,or the like may be placed in the groove or grooves 104 to provide asecondary, or fail safe, seal to prevent leakage in the event of thefailure of the inner diameter seal element 58. In some embodiments, thesecondary seal element is a metal seal, and a compression limiter isplaced in the groove 104, similarly as described in above-noted U.S.Pat. No. 7,976,074, the entire disclosure of which is incorporatedherein by reference as if set out in full. The axially extending sides105 of grooves 104 may be beveled at an angle between about 75 to 90degrees, such as, for example, the radially outward side 105 as shown inFIG. 6. Such a beveled surface provides enhanced retention of a lip sealthat may be disposed in one or both of the grooves 104 such that whenmedia applies pressure to the lip seal, the seal is pressured againstthe inside surface of the beveled groove 104 and thus forced into thegroove 104. As will be understood, the dimensions of the embodiment ofFIG. 6 are exemplary, and other suitable dimensions may be used invarious different applications as will be readily apparent to one ofskill in the art. In non-failure operation, the gasket 50, includingeither retaining ring 54 or 100, is installed in a joint, with the innerdiameter sealing element 58 containing the media within the joint. Inthe event of a failure of the primary seal of sealing element 58, thesecondary seal located in groove 104 may facilitate containment of themedia within the joint.

As discussed above, embodiments of the present disclosure provide aninner diameter seal and retaining ring that are interlocked so as toprevent relative movement between the two. It will be readily recognizedby one of skill in the art that the locking mechanisms between the sealand retaining ring may take on various different configurations. Forexample, FIGS. 8A through 8D illustrate various different configurationsthat may be used to prevent axial and radial movement between an innerdiameter seal element and a retaining ring. FIGS. 9A through 9Cillustrate various different configurations that may be used to preventaxial and radial movement between an inner diameter seal element and aretaining ring. It will be understood that any combination of theseillustrated features, as well as other configurations, may be used toachieve enhanced physical locking of retaining rings and inner diameterseal elements. In various embodiments, gasket seals such as the typesdescribed include an adhesive between the retaining ring and sealelement to secure the two together.

The retaining ring 54 with a curved or tapered surface such as axiallocking element 86, which has a concave shape, and radial lockingelement 82, which has a tapered or angled shape, along with the axiallocking feature 94, which is convex to mate with axial locking element86, and radially locking feature 90, which is a wedge to mate withradial locking element 82, are provided in part to inhibit the innerdiameter sealing element from buckling inwardly during seal expansion asa result of decompression or thermal changes. The interaction of theaxial and radial locking elements and features, as shown in FIGS. 4 and5, provide a less than ideal reaction vector to resist the motion, whichmay result in delamination or the like of the gasket. As shown, theangled reaction vector would be at approximately 45 degrees whereas thegroove and bead reaction vector would be at a tangent somewhere off theperpendicular. With reference now to FIGS. 10 and 11, a retaining ring200 (FIG. 10) and an inner diameter seal element 250 (FIG. 11) areprovided. The vertical and horizontal arrangements of the lockingelements and features, as will be explained below, provide improvedresistance to relative movement as the reaction vectors areperpendicular to the direction of movement.

With specific reference to FIG. 10, the retaining ring 200 is shown inmore detail. The retaining ring 200 has a height H_(r), which will beexplained further below. The retaining ring 200 comprises a corematerial 202, such as a metal or elastic material, and surface materials204(1), 204(2) coated on opposing sides of the core material 202,although in certain aspects neither side or only one side of the corematerial 202 is coated. The coating material may be any materialmentioned heretofore.

The retaining ring 200 provides a radial locking element 206. The radiallocking element 206 comprises a rectangular recess 208 formed in themetal core 202. The recess 208 is formed in the metal core 202 a radialdistance outward from the core inner surface 210 forming an inner rim212 around the inner circumference of the metal core 202.

As shown in FIG. 10, the retaining ring 200 also comprises an axiallocking element 214. The axial locking element 214 is a rectangulargroove 216 formed in the surface material 204 adjacent the radiallocking element 206. The rectangular groove 216, in this exemplaryembodiment, is formed about the circumference of a first material innersurface 218 an axial distance from the core material to form a leg 220that rests on the core material 202. The first material inner surface218 is formed in surface material 204(1). A second material innersurface 222 is formed in the surface material 204(2) on the oppositeside of the core material 202. The first material inner surface 218 isoffset radially outward from the second material inner surface 222. Thesecond material inner surface 222 is aligned with the core inner surface210. The first material inner surface 218 is offset radially outwardfrom the second material inner surface 222 by the distance of the innerrim 212 plus the distance of the recess 208 formed in the metal core202.

With specific reference now to FIG. 11, the inner diameter seal element250 is shown in more detail. The inner diameter seal element 250 has aheight H_(s) that is greater than H_(r). Providing that the innerdiameter seal element 250 has a height H_(s) greater than the heightH_(r) of the retaining ring 200 provides a number of benefits. Onebenefit relates to ensuring compression of the inner diameter sealelement 250 by the confronting flanges surfaces that facilitates apositive seal being formed. Another benefit includes providing for acontrolled compression expansion. In other words, when compressedaxially, the inner diameter seal element 250 attempts to expandradially. The retaining ring 200 inhibits outward radial expansion suchthat the inner diameter seal element 250 tends to radially expandinwardly. The radially inwardly expansion decreases the volume voidratio such that the seal bore is a closer size alignment with the jointbore, which improves corrosion resistance to name one benefit. The innerdiameter seal element 250 has an inner surface 252. The inner surface252 is chevron shaped as discussed above such that media pressure on theinner surface 252 applies force as shown by arrows A tending to seat theinner diameter seal element 250 against the flanges (not shown in FIGS.10 and 11). The chevron or generally concave shape(s) and the like maybe considered a surface to be inwardly converging to a point internal tothe surface, which in this case is the center point.

The inner diameter seal element 250 has a locking portion 254 thatcomprises parts corresponding to the radial locking element 206 and theaxial locking element 214 of the retaining element 202. The lockingportion 254 comprises a hook 256 that hooks about the rim 212 describedabove. The hook 256 may be considered the radial lock for this aspect ofthe technology. The hook 256 of the locking portion 254 comprises a leg258 and a lip 260 that together form a recess 262. The recess 262 issized to fit the inner rim 212. The leg 258 is sized to fit within therectangular recess 208. The lip 260 extends along the core inner surface210 and the second material inner surface 222. In one aspect, theoutward radial movement is resisted by a surface to surface contact.

The locking portion 254 also comprises an axial lock protrusion 264. Theaxial locking protrusion 264 is sized to fit within the rectangulargroove 216 and is generally protruding from the leg 258 rather than thelip 260. The axial locking protrusion 264 forms a circumferential shelfsurface 264s that abuts at least one wall of the rectangular groove 216.As shown, the axial locking protrusion 264 is formed as a wedge having atriangular cross section. The wedge shape facilitates the axial lockingprotrusion 264 engaging with the rectangular groove 216. Thecircumferential shelf surface 264s is generally downstream facing toprovide a surface to surface resistance to axial movement. The wedgeshape facilitates insertion of the axial locking protrusion 264, but theaxial locking protrusion 264 could have a shape sized to cooperativelyfit into the rectangular groove 216, e.g., be a block shape for example.

FIG. 12A shows an elevation view of an isolation gasket 300. FIG. 12Bshows a cross-sectional view of the isolation gasket 300. FIG. 12C showsa detail of the cross section of FIG. 12B. The isolation gasket 300 hasa retraining ring 302 and an inner seal 304 similar to the abovedescribed technology. The isolation gasket 300 also has a C-clamp 306interspersed between the retaining ring 302 and the inner seal 304. Theinner seal 304 is generally formed of a the material identified abovefor the inner seal elements. The C-clamp 306 may be formed of anon-conductive material, such as ceramics, composites, and the like, ormetals. The retaining ring may be formed from a non-conductive materialas well but typically is a metal. When formed from metals, the C-clamp306 and the retaining ring 302 have non-conductive material applied tothe surfaces, such as the material 204 described above.

With reference to FIG. 12C, the retaining ring 302 is shown having afirst axial height of H1. The retaining ring 302 has an inner retainingring surface 308 that has a first shape 310. The shape 310 in thisexemplary embodiment is a concave shape, which will be explained furtherbelow. The inner retaining ring surface 308 cooperatively engages anouter C-clamp surface 312 of the C-clamp 306. The outer C-clamp surface312 is convex, which is shaped to cooperatively engage the innerretaining ring surface 308. Other shapes of the inner retaining ringsurface 308 and the outer C-clamp surface 312 are possible. While shownis similar shapes, the shapes may be different. For example, the C-clamp306 may have a E-shape, which would provide a convoluted outer C-clampsurface 312, and the inner retaining ring surface 308 may still be aconcave shape to cooperatively engage the outer C-clamp surface.

The C-clamp 306 has an inner C-clamp opening 314, which is opposite theouter C-clamp surface 312. The C-clamp 306 has seal arms 316 extendingfrom the outer C-clamp surface 312 to the inner C-clamp opening 314. Theseal arms 316 have an apex 318, which is shown approximately ½ theradial distance between the outer C-clamp surface 312 and the innerC-clamp opening 314. The apex 318 has an uncompressed axial height H2,which is greater than the axial height H1. Thus, when the isolationgasket 300 is compressed, the axial height of the C-clamp 306, at leastat the apex 318, will decrease causing ends 320 of the seal arms 316 toapproach each other, in other words, the inner C-clamp opening 314 willdecrease in size, which will be explained further below.

The inner seal 304 has an inner seal surface 322 and an opposed outerseal surface 324. The inner seal 304 has a protrusion 326 (or annularridge 326) extending from the outer seal surface 324. The inner sealsurface 322 is shown as having a chevron shape. The protrusion 326 isshaped to fit within the C-clamp opening 314. In this exemplaryembodiment, the protrusion 326 is a block shape, but other shapes arepossible. The inner seal 304 has an uncompressed axial height H3, whichis greater than axial height H2.

The inner seal 304 has an outer diameter to the outer seal surface 324.The outer diameter in certain embodiments may be slightly larger thanthe inner diameter of the C-clamp 306 at the C-clamp opening 314. Theslightly larger outer diameter ensures the inner seal 304 forms a snapfit connection with the C-clamp 306. The inner seal 304 may expandaxially into the C-clamp 306 through the inner C-clamp opening 314 incertain configurations. In certain embodiments, the inner seal 304 maybe compressed radially to fit within the C-claim 306 and allowed toun-compress radially to for a friction fit with the C-clamp 306.

As explained above, the ends 320 of the seal arms 316 will move towardseach other when the C-clamp 306 is compressed by the joint duringinstallation. The ends 320 in certain embodiments may compress ontoopposing surface 328 of the protrusion 326, which may grip the innerseal 304. In certain embodiments the ends 320 may pierce the surfaces328 of the protrusion 326 to enhance the connection between the innerseal 304 and the C-clamp 306.

As can be appreciated, the C-clamp 306 also provides a secondary seal.The seal arms 306 proximal the apex 318 form a seal with the jointsurfaces providing the compression. The secondary seal provided by theC-clamp 306 provides for safety in case of a primary seal failure byinner seal 304. The secondary seal provided by the C-clamp 306 alsobecomes a primary seal in certain catastrophic failure situations, suchas fire that destroys the primary inner seal 304. The secondary sealalso provides sealing in the unusual event of the inner seal 304 notbeing retained by the C-clamp 306.

The C-clamp 306 and inner seal are connected by frictional forces andthe ends 320 on the surfaces 328, both of which serve to provide anaxial lock and a radial lock for the inner seal 304. To facilitate theconnection, the surfaces 328 may have one or more axially extendingridges 330.

As will be appreciated by those skilled in the art, industries such asthe oil and gas industry, utilize many, many miles of connected metalpipelines that are subjected, for example, to a natural flow of currentthrough the pipeline and across the metal-to-metal flange connections inthe pipeline which causes the flange connections to corrode and build upcorrosion similar to battery terminals. The isolation gasket forembodiments of the invention interrupts that current flow through apipeline and prevents the flanges from corroding and building upcorrosion in the way in which they would with a metal-to-metal seal.

A method of making the gasket material for embodiments of the inventioninvolves bonding the dielectric lining material to both sides of themetal substrate in large sheets to assure uniformity of the lamination.According to such a method, a water jet is thereafter utilized to cutappropriately dimensioned I.D and O.D. circles for gaskets out of thelarge sheets, and the locking elements are formed on the inner diametercircle of the cut-out circular gasket material, for example, with thecircular gasket material mounted on a lathe. The resulting isolationgasket for embodiments of the invention has the stability and/orrigidity of a metal gasket with a stainless steel core having excellentcorrosion resistance properties, while the glass reinforced epoxylaminated to the opposing surfaces of the gasket provides excellentinsulating properties, and the locking elements provide that an innerdiameter seal may be interlocked thereto. Grooves may be cut into thecircular gasket material using a lathe, as well, in embodiments that usegrooves for secondary sealing elements.

The previous description of the disclosed embodiments is provided toenable a person skilled in the art to make or use the present invention.Various modifications to these embodiments will be readily apparent tothose skilled in the art, and the generic principles defined herein maybe applied to other embodiments without departing from the spirit orscope of the invention. Thus, the present invention is not intended tobe limited to the embodiments shown herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

What is claimed is:
 1. A seal apparatus for use between joined pieces ina flow line that is operative to contain fluid therein, comprising: (A)a retaining ring having opposing side surfaces and an inner diameteropening formed therein, the retaining ring comprising: (i) each of theopposing side surfaces having a dielectric material thereon, and (ii) aportion of a lock mechanism formed on the retaining ring comprising atleast a ridge and a groove formed in at least one of the opposing sidesurfaces of the retaining ring; and (B) an inner diameter seal elementformed of a non-conductive material and having an inner seal surface anda portion of a locking mechanism, the portion of the locking mechanismwhen the inner diameter seal element is mated with the retaining ringcomprising a hook cooperatively engaged with the at least a ridge and agroove formed in at least one of the opposing side surfaces of theretaining ring, wherein the cooperative engagement of the portions ofthe lock mechanism inhibits radial movement between the retaining ringand the inner diameter seal element.
 2. The seal apparatus as claimed inclaim 1, wherein the inner diameter seal element has a first height andthe retaining ring has a second height less than the first height toallow compression of the inner diameter seal element.
 3. The sealapparatus as claimed in claim 1, wherein the dielectric materialdisposed said opposing side surfaces is polytetrafluoroethylene.
 4. Theseal apparatus as claimed in claim 1, wherein the layer of dielectricmaterial disposed on both opposing side surfaces of the metal corematerial comprises a groove.
 5. The seal apparatus of claim 1, whereinthe retaining ring comprises a metal core and a layer of surfacematerial disposed on each of the opposing side surfaces wherein thelayer of surface material forms a secondary seal.
 6. The seal apparatusas claimed in claim 1, wherein said retaining ring further comprises agroove formed on each of said opposing side surfaces and a secondaryseal element is disposed in each of said grooves.
 7. The seal apparatusas claimed in claim 1, wherein the retaining ring has a kammprofile. 8.The seal apparatus as claimed in claim 1, wherein the lock mechanism onthe retaining ring comprises a plurality of ridges and a correspondingplurality of groove.
 10. The seal apparatus as claimed in claim 8,wherein the inner seal surface comprises an inwardly converging surfacethat is pressure activated.
 11. A gasket assembly for use at a jointbetween confronting flanged surfaces, comprising: (A) a retaining ringcomprising a metal core material having a core inner surface, a firstside surface, and a second side surface opposed to the first sidesurface, a first layer of dielectric material on at least a portion ofthe first side surface and a second layer of dielectric material on atleast a portion of the second side surface, wherein the metal corematerial comprises a kammprofile having a plurality of recesses and aplurality of rims in the first side surface and the second side surfacewherein at least inner ones of the plurality of recesses and pluralityof rims form an inner diameter circumferential rim and at least oneaxially extending groove in the first layer and the first side surfaceand at least one axially extending groove in the second layer and thesecond side surface configured to hold a secondary seal element, and (B)a seal element formed from a non-conductive material, wherein the sealelement comprises at least one leg extending radially outward from anouter seal surface of the seal element and over at least the first sidesurface of the metal core material and at least one lip, wherein the atleast one lip extends axially from the at least one leg into at leastthe inner ones of the plurality of recesses to form a radial lock. 12.The gasket assembly as claimed in claim 11, wherein the dielectricmaterial is formed from a polyimide material.
 13. The gasket assembly asclaimed in claim 11 further comprising an axial lock.
 14. The gasketassembly as claimed in claim 11, wherein said inner seal surfacecomprises inwardly converging surfaces that are pressure activated. 15.The gasket assembly as claimed in claim 13 wherein the axial lockcomprises a first part on the retaining ring and a second part of theseal element, wherein: the first part comprises at least a groove in aninner, axially extending surface of at least one of the first and secondlayers, and the second part comprises at least a protrusion axiallyextending from an outer surface of the seal element.
 16. The gasketassembly as claimed in claim 11, wherein the seal element comprisespolytetrafluoroethylene.